Machine for making concrete blocks



Oct. 29, 1929. E wlDlN 1,733,706

MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29, 1928 7 Sheets-Sheet TigE U I W W I Oct. 29, 1929. E. WlDlN MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29, 1928 7 Sheets-Sheet 2 m w n Oct. 29, 1929.

WIDIN MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29,

1928 7 Sheets-Sheet Oct. 29, 1929. E. WIDIN 1,733,705

MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29, 1928 7 Sheets-Sheet 4 :E'i g l E Hvwewtoz Fig Oct. 29, I 529.

E. WIDIN MACHINE FOR MAKING CONCRETE BL OCKS Filed March 29, 1928 7 Sheets-Sheet E. WlDlN MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29, 1928 '7 Sheets-Sheet 6 an wnto'c Oct. 29, 1929.

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(Tet. 29, 1929. E. WIDIN 1,733,706

MACHINE FOR MAKING CONCRETE BLOCKS Filed March 29, 1928 7 Sheets-Sheet II II Ill . INVENTOR BYZQTT NEY,

Patented Oct. 29, v19 29 PATENT OFFICE EDGAR mm, 01' mm, NEW 1mm meant]: 1'03 KING CONCRETE BLOCKS Application filed larch as, me. mm Io. scam.

My invention relates to amethod and mechanism for producing blocks from plastic material such as concrete mixtures.

The general object is to provide improved production of blocks of concrete or analogous material, of variable forms, and more particularly blocks having on one face ribs or corrugations, and also when desired having at one'end transverse shoulders or interlocking formations, such blocks being used, for example, as roofing tiles.

The method comprises char ing a mold or a series of molds with the p astic material such as concrete mixture, and preferably at the same time preliminarily shaping the upper block surface, and subsequently additionally finishing or shaping the upper surface material by scraping or sleeking operations, to produce the desired final top surface formations, without necessity for using upper mold sections or delay and expense which would be incidental to the manipulating of such mold parts. In a preferred form the method also comprises placin a removable plate in the mold bottom be ore charging, and after the scraping or sleeking opera tions, freeing or ejecting the plate from the mold, so that the formed plastic block may conveniently be placed in a drying rack where the concrete sets while supported by the plate without possibility of deformation of the block. The method also includes, when desired, application of coloring material to the block, referably before one of the shaping. or sleefiing operations.

The mechanism in a preferred form, as here disclosed, comprises a conveyor, preferably of circuitous form, means for accurately locating or registering a series of molds thereon at a succession of work positions, and means at successive stations for charging the molds, for sleeking scraping or shaping the upper surface of the plastic material, for applying pulverized material such as paint or other pigment to the block surface,for ads ditionally scraping or sleeking theupper face of the block, and for then freeing or ejecting the sha ed block from the mold by lift- 6) ing the bloc -supp0rting plate therefrom.

N apparatus and methods for the economical to move pistons, under the control 0 valves,

so that the apparatus in its preferred form is entirely automatic.

The characteristics and advantages of the lnvention are further sufliciently explained in connection with the following description of the accompanying drawings, which illustrate one'representative embodiment. After consideri this example, skilled persons will understan that many variations may be made without departing from the principles involved, and I contemplate the employment of any method steps or structures that are properly within the scope of the appended claims. A

Fi 1 to 4 are pzrspective views of one suita le mold and ttom plate, explaining also the operating method.

F1 5 1s a vertical section of the mold, showing also the ejector plate and pins.

Fig. 6 is a plan view, partly diagrammatic, of the complete machine.

Fig. 7 is .a fragmentary elevation of a stretch of the conveyor corresponding to the various work stations, with a series of molds aligned thereat, and showing also the moldpushing mechanism.

Fig. 8 is a section. at 8-8, Fig. 6.

Figs. 9 to 12 are fragmentary, sectional positional views of the mechanism of Fig. 8.

' Fig. 13 is a section at 13-43, Fig. 6.

Fig.14 is a plan of that part of the machine.

Fig. 15 is a section at 1515, Fig. 6.

Fig. 16 is a plan of that part of the machine.

Figs. 17 to 19 are fragmentary, sectional, positional views, explanatory of the mecha nism of Fig. 16.

Fig. 20 is a view of one suitable control system, or; valve mechanism.

Figs. 1 to 5 'llustrate one suitable form of mold 1 and removable bottom plate or block supporting plate 2. The mold form and dimensionsmayvarysubstantiallyinaccordance with the article to be produced. In the present example where the block B is a rectan lar, relatively thin roofing tile having para el side and central ribs or corrugatlons 3 and 4 respectively, with intermediate dgrooves or channels 5, and a transverse en flange or locking rib 6, the urijper face of which is in some cases located a ove the upper faces of the ribs 3 and 4, the mold is of generally s milar contour, including a flat bottom 7 havmg ejecting apertures 8, shallow side walls 9, a front wall 10 and a rear wall 11. The top of the front wall is shaped in accordance with .the surface formation of the block B; i. e. it has recesses 12 corresponding to the blockgrooves 5, and upper surfaces 13 and 14 corresponding, respectively, to the block ribs 3 'and 4. The side walls are provided with I the upper sur ace of the flanges 15 terminating in lips 16, forming open-ended sockets in WhlOh registering stops fit, in the operation of the machine, as later described. An ejector plate 18, forming a part of the machine, is provided with ms 19 to pass through the ejector holes 8. e under face of the mold is rovided with channels 20 to cooperate wit guide rails of the machine, as later explained.

The method of producing the blocks, as carried out in one preferred manner by the operation of the machine, as later explained, com prises placin a supporting late 2 in the bottom of a mol (Fig. 2) and c argmg the mold (Fig. 3) with an approximately accurate quantity of plastic material, such as a su1table concrete mixture 0, and in the operation of charging the uppgr surface of the material may in some cases a as more fully described in the operation of the machine. The surface formation, including the ribs and channels 3, 4 and 5, and the transverse .rib or shoulder 6 are then accurately formed by scraping or sleeking operations, and before the final smoothing or sleeking operation, if desired, suitable coloring material, such as ulverized paint, is applied to lock; and then in the final smoothing or sleeking operations this material is substantially incorporated in the moist upper surface of the concrete. The ejecting pins 19 are then applied through the mold holes 8, and the bottom plate 2 carrying the block is elevated for convenient removal from the mid and placing upon a drying rack, where the block dries accurately in true form, being supported by the bottom plate without possibility of deformation. The bottom plate may, when desired, have on its upper surface a rib formation 21 (Fig. 2) to produce a corresponding recess in the bottom of the block. The machine, as illustrated in Figs. 6 to 20, comprises a continuous or circuitous conveyor 25, the structure or arrangement of which may vary. In a referred form the conveyor is, as shown su stantially elliptical with straight stretches 26 and 27 connected by The conveyor is desi pproximately shaped,-

curved portions of the conveyor comprise side frame strips 29 and 30 and a center strip 31,

and rollers 32 mounted between the strips. ed to circulate the molds largely by gravity, and for that purpose it has its lowest int at 33 atthe beinning of the straig t stretch 26, and its ighest point,at 34 at the end of the straight stretch 26, and this portion of the conveyor is arran ed as an elevator consistin of a belt 35 runmn over-pulleys 36 and 3 the latter being riven inany convenient way, as by an electric motor 38 and gearing 39. From the upper end of the conveyor 35 the curved portion 28 of the conveyor constitutes a descending run-way to the beginning of the straight conveyor stretch 27. This rtion of the conveyor is horizontal and is provided withlongitudinal rails 40 to co-operate with the mold channels 20 above mentioned. From the other end of the straight conveyor portion 27 the curved portion 28 descends to the point 33, i. e. the take-up end of the elevator 25.

The molds remain on the conveyor in a practically continuous series, one of the molds being shown'at the be 'ng of its descent from the discharge an of the elevator, and seven of the molds being shown in proper registry and alignment, occupying the straight stretch 27 of the conveyor where the charging, shaping discharging and other operations are per ormed. The other molds are omitted in Fig. 6 for the sake ofillustrative clearness.

The series of molds occupying the straight conveyor stretch 26 at any time consists, in the present arrangement, of seven molds in end-wise contact and properly registered in relation to the charging and other mechanisms by bolts 41 arranged in pairs, each pair being carried by a yoke '42 operated by pneumatic mechanism, including a cylinder 43 containing a piston (not shown), which is connected to the yoke by a piston rod 44.

To properly register the series of molds in cooperation with the stops or bolts 41, a cylinder 45 is mounted a ove'the conveyor and in advance of the straight stretch 27. This cylinder is pivotally supported, (Fig.

7) as at 46, on a column 46, and has a piston' connected with a mold-pushing plunger 47. Another cylinder 48, is provided to raise and lower the free end of the cylinder 45. After the performance of each set of operations with relation to the molds located on the straight conveyor stretch 27, the registering bolts41 are retracted and the plu er 47 is operated to engage an adjacent molifand push the entire series forward a distance of one mold length, whereupon the bolts 41 are advanced an enter the ends of the socket formations consisting of flanges 15 and lips 16 of the mold, which is then locked in a sition between the cylinders 43, this g action -1o n s 30 having piston rods 55 conn stated mold-advancing o ration one mold is dischar at the end the series, and this travels y gravity around the curved stretch ntherollers32andguidedb the outer an inner strips 29 and 30. formed block was removed from the mold after an ejecting action at the last work station and when the empty mold reaches the point33afreshbottom plate7isplacedin 1t, and the mold is then carried the elevator 35 to its discharge point an descends by gravity around the curved stretch 28 to a point ad acent to the beginning of the conm veyor stretch 27 ready for another advancin operation by the pushing plunger 47, an so on. At a first work station, at the beginmn of he straight conveyor stretch 27, is charg- 5 ing mechanism, including an upright ho per 50(Figs.8to12). Thisissup rted a frame 51 having sleeves 52 gm ed for vertical reciprocation on upright him 53. The hopper is raised and lowerigy cylinders 54 to the frame. The lower end of the hopper co-operates substantially with the upper face of the mold 1, and is provided with a horizontally-reciproeating gate or blade 56, which may be flat, or as otherwise may be shaped in substantial accordance with the u per face of the mold or block to be produ The blade 56 is connected to a piston rod 57 operated by a cyhn- .der 58 carried by frame 51. After the positioning of the mold beneath the hoper, while the latter is in elevated position, as shown in Fig. 8, the hopper is lowered until the gate or blade 56, which is at that time in active position closing the lower end of the hopper, rests upon the upper face of the mold, as shown m Fig. 9. The blade or gate is then withdrawn by suitable operation of the cylinder 58, permitting the concrete mixture in the hopper to descend and fill the mold, as shown in Fig. 10. The blade is then returned to active position, as shown in Fig. 11, in effect severing the mold charge from the mass contained in the hopper, and the hopper is then retracted upward, leaving the mold properly charged, as shown in Fig. 12. When the plate is conformed in accordance with the desired upper formation of the block (or substantiall in accordance with the contour of the mol end wall 10) the upper surface of the plastic material is at the same time preliminarily shaped or formed, although this feature may be omitted, and in that case, the gate or blade 56 is flat..

The filled mold is then advanced by the pushing and registering operations previas] explained, thro h an idle 'tion as at 65, to the. next wor k station, (1' 14) where means are provided for scraping or sleekmg operations to shape, or additionally shape, the upper face of the plastic materm]. At this station is a frame 61 extendmg across the conveyor and pivotall supat 62. The frame is omilla by a cylinder 63 supported on a bracket 64 and having a piston rod 65 pivotally connected to the frame at 66. The frame structure includes guide rods 67 slidably sup rting a sleeker or scra r 68, the lower e e 69 of which is shape in conformity with t e upper face of the mold wall 10 and of the block. The scraper is reciprocated by a cylinder 70 sup frame 61 havm a piston rod 71 connec to the scraper. the mold is advanced to a position beneath frame 61 the right hand portion of the frame, as viewed in Fig. 13, is elevated b proper operation of cylinder 63, the Weig t of the overhanging g frame portion being suitably counterbalanced by weights 72, and these counter weights may be varied to re ate the pressure with which the scraper wi bear upon the plastic mate rial in the mold. The cylinder 63 is operated to lower the scra r or sleeker 68 to the level of the u per su ace, and cylinder 70 is. then operat to move the scraper to the left, as viewed in Fig. 13, thus scraping or 'sleeking to proper form the upper sur ace of the block. The stated movements of the scraper may be terminated at about the point indicated in dotted lines at 68; i. e., at a point spaced from the outer mold wall 11, to roperl form the vertical inward face of the bloc rib 6; and, if desired, the scraper may have a horizontal flange or shoulder 73 to overlie and properly form the upper surface of rib 6. In accordance with one plan of operations the cylinder 70 may then be-operated to return the .scraper to its right hand position, thus performing two successive scraping or sleekmg operations in opposite directions,

after which the frame will be oscillated to raise the scraper and permit the mold to advance to the next station. Otherwise the cylinders 63 and 70 may be controlled to perform the above-described single scraping or sleeking operation upon a given block, i. e. by movement from its right hand position, as shown in Fig. 13, to the left hand position, as indicated in dotted lines, and then the frame may be oscillated to lift the scraper, the mold advanced and a fresh one p0sitioned, and'then the scraper may be lowered and moved to the-right to perform its scrapigs. 13 and ing or sleeking operation upon the stated '1 block during its return or right hand movement; or, in brief, the scraping operations upon successive molds or blocks are in this case performed by alternately-directed movements of the scraper.

The mold is then advanced to another work station, where colorin material is applied, if desired, to the upper ace of the block. For this purpose a sieve or screen 75 is located above the conveyor and supported for reciprocation upon guides 76. A cylinder 77 has a piston rod connected to the screen, which is filled with suitable coloring material, such as pulverized paint; the screen is shaken by proper operation of the cylinder 77 to deposit a desired amount of the coloring material upon the upper surface of the moist block.

The mold is then advanced to the next work station, at which means is provided, when desired, for performing another and final smoothing or sleekingoperation upon the block. Mechanism for this purpose includes, as shown in Figs. 15 to 19'guide rods 78 supported by transversely-extendin brackets 79 and 80. Frame 81 is provide with sleeves 82 mounted for reciprocation upon rods 78. The frame is moved to and fro by a piston rod 82 operated by cylinder 83 supported on bracket 80. The frame has vertical guide ways 84 in which are mounted vertical rods 85, the lower ends of which support an angular sleeking or scraping blade 86.

The upper ends of the rods are connected to a block 87 having an angular cam face 88. Another block 89 is mounted for reciprocation in relation to the frame 81 and has an angular cam face 90 co-operating with the cam face of block 87. Block 89 is connected to a piston rod 91 operated by a cylinder 92 supported on bracket 79. In a preferred operating method, by proper control of the cylinders 83 and 92 with the parts in the I position shown in Figs. 15 and 17, block 89 is first moved to the ri ht in relation to frame 81, permitting block 8% and the scraper 86 to descend, whereupon as in Fig. 18 the left hand edge of the scraper blade acts upon the vertical inward face of the block rib 6 and completes its proper formation, and then by co-operative movement of rods19 and 82 the frame 81 is moved to the right, causing the scraper to smooth down and properly sleek or form the upper surface of the block, including the rib formation 3 and 4 and the grooves or channels 5; and thereafter block 89 is moved to the left in relation to frame 81 while the frame is in right hand position (Fig. 19) and the scraper is thus elevated, and thereafter the frame 81 is moved back to left hand position, as shown in Figs. 15 and 17, with the scraper out of contact with the block during such return movement.

In the stated scraping operation the pulverized coloring material previously depos-' ited upon-the surface of the block is practically intermixed'with or incorporated in the upper layer of the block material so that when the concrete sets the coloring material is permanently incorporated m the block surface. The mold is then advanced through an idle position, to the final or registering position between cylinders'43, and at that point the ejecting action-is performed.

For this purpose the ejector plate 18, as described with reference to Fig. 5 is located beneath the conveyor .and its eject' pins 19 arranged to reciprocate in 'des fiigned with the ejecting holes 8 of t e mold. The plate is operated by a suitable pneumatic cylinder and this cylinder is operated to raise the plate and move the pins through the model holes, and thus to lift the bottom plate 7 to a convenient position, as shown in Fi 4 for the removal of the plate carrying 1: e formed block, which is placed in a rack for drying or setting.

The empty mold then proceeds around the curved conveyor stretch 28 to substantially the point33, where a fresh bottom plate is inserted in it, and it is raised b the elevator 35, ready for another circuit 0 the machine, as sufliciently explained above.

Any known or suitable means ma be provided for the proper control of t e pneumatic cylinders above referred to. Fig. 20 sufliciently illustrates one suitable arrangement or system for cylinder control. In this figure the respective cylinders are identified by the same reference characters as in other figures. Each cylinder is provided with one or two air lines 100, each air line leading to suitable valve mechanism 101, the valve mechanism for each air line including, in the present example, two valves 102 and 103, which may be simple piston valves, the pistons 104 of which are operated by cam 105 fixed at suitable angles upon a cam shaft 106 driven by any suitable means. For each valve an, one of the valves, as 102, controls air supply to the cylinder from any suitable source such as a tank or accumlator, (not shown) and the other valve, such as 103, controls exhaust of air from the cylinder to atmosphere, and thus by the provision of one or two air lines for each cylinder, depending upon whether the piston thereof is positively moved in only one or in two" directions, the operation of the respective piston may be properly controlled for the various purposes described above.

While the mechanism described may be and preferably is entirely automatic in operation, it is not necessarily so, since in some cases where simplification and reduction in cost of equipment is desirable, the mechanism at some'or all of the different work stations may evidently be independently or manually operated or controlled.

What I claim is:

1. Mechanism of the class described, comprising a continuous conveyor for circulatmg a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, means for definitely advancing and positioning a series of molds at the work stations, and means at and. sha ing the u r surface of 'theplastic materiaf in the mo and means ata subsenvaavoa one work station for charging the molds with a measured uantity of plastic material and simultaneous y approximately shapmg the upper surface of the material, and means at a subsequent work station for scrapmg quent work station for depositing pulverized coloring'material u n the surfaceof the plastic material, an means at'a su uent work station for scraping and finally aping the upper surface of the plastic material and simultaneously incorporat ng the coloring material therein, and means at a final work station for lifting the aha block of plastic'material from the mol 2. Mechanism of the class described, comprising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurahmf successive work stations, a hopper at a work station, means for raisin and lowering the hopper in relation to a mo (1 podtioned below it, a reciprocable gate normally closing the bottom of the hopper, and means for rec1proeating the to to charge the mold with plastic material from the hopper and to separate the mold charge from the superposed mass m the hopper, a scraper arranged for vertical and transverse reciprocatin movements in relation to a mold position at a subsequent work station, and means for operating the scraper to traverse the surface of plastic material m the mold and shape the same.

3. Mechanism of the class described, comprising a continuous conveyor for circulatmg a series of molds, said conveyor having a portion corresponding to a plurality of successive workstations, a hopper at a first work station, means for raising and lowerin the hopper in relation to a mold position below it, a reci rocable gate normally closing the bottom of the hopper, and means for reciprocating the to to charge the mold with plastic material m the hopper and to separatethemoldcharge fromthe supe mass in the hopper, a screen for ulvenzed colorin material located above su 't colorin materlal upon the lastic material in the mo (1.

4. Mec anism of the class described, com- 1 prising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, a hopper at a first work station, means for raising and lowering the hopper in relation to a mold positioned below it, a reci rocable gate normally closing the bottom 0? the hopper, and means for reciprocating the gate to charge the mold with plastic material from the hopper and to separate the mold charge from the superposed mass in the hopper, a screen for pulverized coloring material located above the conveyor 0 conveyor at a out work station, and means for agi .tating the screen to do at a sat work station, and means for agitating e screen to deposit coloring matenal upon the plastic'material in'the mold, a scraper arranged for vertical and transverse reciprocation in relation to a mold positioned at a subsequent work station, and means for moving the son vertically and transverse- 1y to smooth an shape the upper surface of plastic material in the mold; 4

- 5. Mechanism of the class described, com

- prising a continuous conveyor for circulating a series of mol said conveyor having a portion corresponding to a plurality of successive'work stations, a hopper at a first work station, means for raising and lowering the hopper in relation to a mold positioned below it, a reciprocable gate normally closing the bottom' of the hopper, and means for reci rocating the to to charge the mold with p '0 material m the hopper and to separate the mold charge from the superposed mass in the hopper, a scra r arranged for vertical and transverse reci rocating' move ments in relation to a mold? positioned at a subsequent work station, and means for operating the scraper to traverse the surface of plastic material in the mold and shape the same, an ejector plate arranged for vertical reciprocation beneath the conveyor at a subsequent work station, ejector pins on the plate toco-o witha resmthe bottom of the mo d and a bottom plate located in the mold -to support the plastic material, and means for operatingrthe ejector plate to raise the bottom plate in the mold for convenient removal of said plate with the plus tic block sup rted thereon.

B Mechamsmof the class described, comprising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, means for definitely advanclng and positioning a series of molds at the work stations, a hopper at a first work station, means for raisin and. lowering the hopper in relation to a mo d positioned below it, a reciprocable gate normally closing bottom-o the hopper, and means for reciprocating the gate to charge the mold with plastic materia from the hopper and to separate the mold charge from the supe d mass. in the hopper, a scraper arranged for vertical and transverse reciprocating movements in relation to a mold positioned at a submuent work station, and means for operating the scraper to traversethe surface of plastic material in the mold and shape the same.

7 Mechanism of the class described, comprising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, means for definitel advancing and 'tioning a series of mold s at the work stations, a hopper at a first work station, means for raising and lowering the the.

hopper in relation to a mold positioned below it, areciprocable gate normally closing the bottom of the hopper, and means for reciprocating the gate to charge the mold with plastic material from the hopper and to separate the mold charge from the superposed mass in the hopper, a scraper arranged for vertical and transverse reciprocating movements in relation to a mold positioned at a subsequent work station, and means for operating the scraper to traverse the surface of plastic material in the mold and shape the same, a screen for ulverized coloring material located above the conveyor at a subseuent work station, and means for agitating t e screen to deposit the coloring material upon the plastic material in the mold.

8. Mechanism of the class described, comprising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, means for definitel advancing and positioning a series of mol at the work stations, a hopper at a first work station, means for raisin and lowering the hopper in relation to a mo d positioned below it, a reciprocable gate normally closing the bottom of the hopper, and means for reciproeating the gate to charge the mold with plastic material from-the hopper and to separate the mold charge from the supe osed mass in the hopper, a scraper arrange for vertical and transverse reciprocating movements in relation to a mold positioned at a subsequent work station, and means for operating the scraper to traverse the surface of plastic material in the mold and shape the same, a screen for pulverized coloring material located above the conveyor at a subsequent work station, and means for agitating the screen to deposit the coloring material upon the plastic material in the mold, a scraper arranged for vertical and transverse reciprocation in relation to a mold positioned at a subsequent work station, and means for moving the scraper vertically and trans versely to smooth and shape the upper surface of plastic material in the mold.

a 9. Mechanism of the class described, comprising a continuous conveyor for circulating a series of molds, said conveyor having a portion corresponding to a plurality of successive work stations, means for definitely advancing and positioning a series of molds at the work station, a hopper at a first work station, means for raising and lowering the hopper in relation to a mold positioned below it, a reciprocable gate normally closing the bottom or" the hopper, and

means for reciprocating the gate to charge the mold with plastic material from the hopper and to separate the mold charge from the superposed mass in the hopper, a scraper arranged for vertical and transverse reciprocating movements in relation to a mold positioned at a subsequent work station, and means for operating the scraper to traverse the surface of plastic material in the mold and shape the same, a screen 'for pulverized colorm material located above the conveyor at a su sequent work station, and means for agitating the screen to deposit the coloring material upon the plastic material in the mold, a scraper arranged for vertical and transverse reciprocation in relation to a mold positioned at a subsequent work station, and means for moving the sore r vertically and transversely to smooth an shape the upper surface of plastic material in-the mold, an e ector plate arranged for vertical reciprocation beneath the conveyor at a subsequent work station, ejector pins on the plate to 00 operate with e ector holes in the bottom of the mold and a bottom plate located in the mold to support the plastic material, and means for operating the ejector plate to raise the bottom plate irom the mold for convenlent removal of said plate with the plastic block supported thereon.

In testimony whereof I afix my signature. 

